Well if you’re arguing that walking replace cars, your 5 mile radius thing doesn’t work any better than trains. And economically viable is still relevant even if you are talking taxes and subsidies. I’m 100% in favor of trains and public transport, but that 5 and 30 mile radius is only meaningful when people are grouped in close proximity…if I only share my 30 miles with 10,000 other people, and that 30 miles is even vaguely diffuse, you cant draw up a map where a train schedule works without making have of the 10,000 people employees of the train station.

Move half of the rural population into more rural areas and you get closer to that ideal, but how do you ‘move’ people in a free country? We have a shitload of land, and a significant number of people living spread out in a way that mass transit just doesn’t make sense because not enough of them are going in the same direction at the same time to make it make sense. Even at the subsidy point, you can’t raise taxes to pay for something that doesn’t raise enough taxes to pay for itself. Just throw a dart at a map in the US and come up with a way to make a passenger train make any kind of sense within a thirty mile radius of the dart. Then, after throwing the dart a thousand times and realizing most of your hits don’t contain even 1000 people, eliminate all those areas and start throwing the dart again. Then, after a thousand hits and realizing that even then you aren’t hitting places where more than 10 people are all traveling in the same direction from the same place more than once or twice a day, maybe you’ll realize the futility of trains solving problems in most of the US.

That being said, the places where it does make sense, I’m 100% in support of exploring all kinds of ways to reduce usage of individual cars, electric or otherwise.